The invention relates to methods for manufacturing precisely wound and positioned magnet coils and, more particularly, relates to such methods for manufacturing superconductor magnet coils that are adapted for use as trim coils in a cryogenic superconducting-super-collider (SSC) particle accelerator having a particle beam path that is encased by a beam tube of relatively small diameter. A superconducting super collider uses thousands of dipole magnets that are carefully designed to exhibit minimal magnetic field harmonics. However, because of superconductor magnetization effects, iron saturation and conductor or coil positioning errors, certain harmonic errors are possible and must be corrected by use of multipole correctors called trim coils. The trim coil assemblies are secured to the beam tube, which comprises an ultra-high vacuum, a (UHV), tube with special strength, size, conductivity and vacuum properties.
At the present time a number of different accelerator magnet systems are being developed for various types of cryogenically cooled particle accelerators. It is anticipated that for accelerators of the SSC type important physics experimentation will be conducted by accelerating different kinds of particles, respectively, in opposite directions in the two intersecting rings of such accelerators; for example, protons may be accelerated in one ring while heavy ions would be accelerated in the other ring. It is recognized that in order to accomplish such experiments, the magnetic field used to accelerate particles in the two rings of such an accelerator must differ significantly. It is also recognized that the accelerator bore diameters in the two rings will be relatively small, i.e., in the range of about 70 to 80 microns. As a consequence, it is necessary in the design and operation of such accelerators to tightly control the flux patterns developed along the particle bores by the accelerator magnets. Typically the construction of such magnets involves stacking a yoke of magnetic iron to surround the accelerator beam tube by a predetermined appropriate diameter. Such a yoke provides a suitable flux return path for the accelerator magnetic field system. In operation, the entire magnet assembly, including the energizing field coils and the magnetic iron yoke assemblies, are encased in a stainless housing that is cryogenically cooled with liquid helium or some other suitable cooling agent.
It has long been known that a desired magnetic flux pattern for accelerating particles through an accelerator bore tube can be fine-tuned or trimmed by precisely positioning a number of magnetic trim coils at selected points along the bore tube surface. The use of such trim coils is, however, significantly complicated in cryogenic accelerator environments due to the problems inherent in inevitable major temperature excursions, as well as those inherent in the use of necessarily very small-diameter superconductor magnetic cable. Another significant manufacturing problem encountered in making suitable trim coils for such superconducting supercollider accelerator assemblies is that the coil windings must extend over several meters in length while maintaining precise close and uniform spacing between adjacent turns of the coils, and at the same time maintaining precise-tolerance spaced relationship of the coil turns relative to the accelerator bore tube, and thus to the associated acceleratror magnet fields.
Whatever means are used to position the trim coils in operating relationship on a bore tube, and to secure the coils in that position, the selected means must be capable of withstanding temperature excursions of several hundred degrees Kelvin. In addition, the coil positioning and securing means must be able to endure the corrosive effects of radiation resulting from movement of accelerated particles around the curved path of the accelerator bores. Finally, mounting a superconducting magnet trim coil in such a precise fashion on the curved, generally cylindrical outer surface of an accelerator beam tube poses other difficult problems in the manufacture and design of suitable methods for making such an assembly. Those problems will be discussed more fully below.